After beleaguered hedge fund managers had their worst month in seven years, many are bracing for an industry D-Day: Nov. 15.

That’s the deadline for investors to put managers on notice to get some -- or all -- of their money at year end.

If history is any guide, the rush for the exits will be swift and accelerate. Clients have already pulled US$11.1 billion even before funds fell into the red for the year.

The last time the industry careened toward annual losses was in 2015, when managers were tripped up by events including the unexpected surge in the Swiss franc and the devaluation of the Chinese yuan. The fallout: clients withdrew US$77.2 billion between the fourth quarter of that year and the first quarter of 2017 -- the biggest withdrawals since the global financial crisis.

Investors can cash out of most hedge funds quarterly after giving 45 days notice. Withdrawal schedules can vary, as do notice periods. Firms can also levy penalties on clients who want to bail outside of agreed schedules, while investors can cancel redemption plans if they change their minds.

Redemptions are yet another blow for the US$3 trillion industry, which has been blighted by years of mediocre performance and fund closures. Several managers have announced plans to shutter in anticipation of year-end withdrawals.

The industry lost 3 per cent in October and is down 1.7 per cent this year, according to Hedge Fund Research Inc. U.S. equities had their worst month since 2011.

Still, it may not be all doom and gloom. As some investors prepare for an end to the years-long bull market, they may add money to hedge funds whose managers tout an ability to better navigate downturns.

Despite the current woes, withdrawals during 2008 were much more acute. They amounted to 11 per cent of the industry’s assets at the time, according to calculations based on HFR data. By contrast, in 2016 redemptions were just 2.3 per cent and so far this year it’s less than 1 per cent.

That may be no solace to fund managers on Nov. 15.